INTRODUCTION Hypovolemia and hypovolemic shock are life-threatening conditions that occur in numerous clinical scenarios. Near-infrared spectroscopy (NIRS) has been widely explored, successfully and unsuccessfully, in an attempt to use it as an early detector of hypovolemia by measuring tissue oxygen saturation (StO2). In order to investigate the measurement site dependence and probe dependence...

Heat stress profoundly impairs tolerance to central hypovolemia in humans via a number of mechanisms including heat-induced hypovolemia. However, heat stress also elevates plasma osmolality; the effects of which on tolerance to central hypovolemia remain unknown. This study examined the effect of plasma hyperosmolality on tolerance to central hypovolemia in heat-stressed humans. With the use of...

Hypotension during intermittent hemodialysis is common, and has been attributed to acute volume shifts, shifts in osmolarity, electrolyte imbalance, temperature changes, altered vasoregulation, and sheer hypovolemia. Although hypovolemia may intuitively seem a likely cause for hypotension in intensive care patients, its role in the pathogenesis of intradialytic hypotension may be overestimated.

We analyzed the heartbeat time series of 12 human subjects exposed to progressive central hypovolemia with lower body negative pressure. Two data processing techniques based on wavelet transforms were used to determine the change in the non-stationary nature of the time series with changing negative pressure. Our results suggest that autonomic neural mechanisms driving cardiac interbeat interva...

GENERAL COMMENTS The authors present a well designed case control study to assess the utility of lab tests suggesting hypovolemia to predict the odds of experiencing a fall in hospitalized patients. While the study has a robust statistical analysis based on good methodological design a couple of assumptions are erroneous to allow appropriate clinical interpretation of numerical data. 1. Hyponat...

Dinh, Thu T., Francis W. Flynn, and Sue Ritter. Hypotensive hypovolemia and hypoglycemia activate different hindbrain catecholamine neurons with projections to the hypothalamus. Am J Physiol Regul Integr Comp Physiol 291: R870–R879, 2006. First published May 4, 2006; doi:10.1152/ajpregu.00094.2006.—To better understand the involvement of hindbrain catecholamine neurons in hypovolemia-induced se...

Preterm infants are at high risk of death and disability resulting from brain injury. Impaired cardiovascular function leading to poor cerebral oxygenation is a significant contributor these adverse outcomes, but current therapeutic approaches have failed improve outcome. We re-examined existing evidence regarding hypovolemia concluded that in the preterm infant loss plasma circulation results ...

The subarachnoid space around the optic nerve can be detected by fat-saturated T2-weighted MR imaging of the orbit, and dilation of this space reflects increased intracranial pressure. We examined 3 patients with CSF hypovolemia with MR imaging of the orbit and measured the optic nerve sheath diameter before and after treatment. We showed that the subarachnoid space is decreased in patients wit...